WO2008129166A1

WO2008129166A1 - Canula/optic fibre assembly and laser tool including said assembly

Info

Publication number: WO2008129166A1
Application number: PCT/FR2008/000264
Authority: WO
Inventors: Jaouad Zemmouri; Jean Ringot
Original assignee: Optical System & Research For Industry And Science Osyris
Priority date: 2007-03-02
Filing date: 2008-02-29
Publication date: 2008-10-30
Also published as: US20080215041A1; FR2913192B1; JP2010519947A; FR2913192A1; EP2114279A1

Abstract

The assembly (E) of the invention includes a canula (2) that comprises an opening (210) at a so-called distal end (21c) and an electromagnetic radiation guiding means including an optic fibre (1) inserted into said canula (2) for guiding an electromagnetic radiation up to the distal opening (210) of the canula, so that the electromagnetic radiation is transmitted in a frontal manner by said distal opening (210) in the canula (2). The outer diameter (D1) of the protective sheath (11) of the optic fibre (1) is substantially equal to the inner diameter (d2) of the canula (29 at least in a distal portion of said canula. The core (10) of the optic fibre is exposed on a distal portion (100) of the fibre, and the exposed distal portion (1009 of the optic fibre is totally located inside the canula (2).

Description

CANNULA / FIBER OPTIC SET AND LASER INSTRUMENT

COMPRISING THIS ASSEMBLY

Technical area

The present invention relates to a new assembly comprising an optical fiber introduced inside a cannula, and the use of this assembly cannula / optical fiber to produce a laser instrument for use in the medical field.

Prior art

In the medical field, it is common to use needles enclosing an optical fiber, the optical fiber for transmitting a laser beam from a laser energy source, for treating or diagnosing diseases. This type of assembly, using a laser energy source, can be used in many medical fields, in particular for the treatment of varicose veins, for the treatment of adipose, for percutaneous diagnosis or in the field of surgery. ophthalmic. The applications of this type of set are thus multiple as well as the constraints related to each application.

For example, commonly, in the case of treatment and reduction of adipose or subcutaneous fat cells, the liposuction technique of introducing a probe having a diameter of about 5 mm under the skin is used. of a patient and to suck the fat. Also, it is common to use an ultrasound probe introduced under the skin of a patient to destroy the fat cell membrane. In the latter case, during the destruction of the membrane, a liquid escapes and must also be sucked. These two techniques have the drawbacks of lack of homogeneity in the treated areas, and cause bleeding of the patient in particular because of the size of the perforations made in the skin of the patient.

For these reasons, a new technique and a new device, described for example in US 6 206 873, have appeared. The device comprises an optical fiber, which is positioned within a cannula, which is connected at its proximal end to a laser energy source and which emits a laser beam (electromagnetic radiation) at its distal end. The cannula is constituted by a hollow needle, whose distal end is open and tapered, and reveals the distal end of the optical fiber.

The technique involves piercing the patient's skin, introducing the needle into a subcutaneous layer of fat cells of the patient, and irradiating said fat cell layer with the laser beam. Irradiation with the laser beam causes lipolysis of the fat layer and causes rupture of the adipose cell membrane, thereby transforming the cells into a liquid substance. This liquid substance can be aspirated or is preferably left in the state to be drained by the lymphatic system and by the action of phagocytes. The technique described in this document allows for uniform treatment of a layer of fat cells while eliminating bleeding problems of the patient and decreasing the size of the perforations in the skin of the patient. The bleeding of the patient is indeed eliminated thanks to the use of the energy of the laser beam to cauterize the blood vessels. The needle / fiber optic assembly described in this US publication

6,206,873 has the following main drawbacks.

A first disadvantage arises from the fact that the distal end of the optical fiber protrudes from the distal opening of the needle. This results in a risk of rupture of the optical fiber during the implementation of the device in the human body, which is extremely detrimental and can be dangerous for the health of the patient.

An optical fiber conventionally comprises three concentric parts:

a central part, for example in S10 ₂ (doped or not), ensuring the guided propagation of electromagnetic radiation,

a very thin intermediate layer (for example SiC 2 or polymer), generally referred to as "dadding", surrounding the central part, and having a refractive index different from the central part, so as to confine the electromagnetic radiation in the central part, a thicker mechanical polymer protective sheath.

In the present text, including in the claims, the term "core", the central part and the middle layer ("cladding") of the optical fiber, and the term "sheath" means the mechanical protective sheath. supra. To improve the emission of the laser beam and avoid burning the sheath surrounding the core of the optical fiber, it is preferable in practice to strip the core of the optical fiber at its distal end. The core of the optical fiber thus stripped is no longer protected at the distal end of the fiber by the mechanical protection sheath surrounding the core of the fiber. But the heart of the optical fiber is very fragile mechanically, which significantly increases the risk of rupture.

A second disadvantage is related to the immobilization of the optical fiber relative to the needle. In the device of the aforementioned publication

No. 6,206,873, the optical fiber is immobilized with respect to the needle by means of a mechanical clamping system comprising an elastic ring, through which the optical fiber is passed, and a clamping screw.

This mechanical clamping system does not reliably immobilize the optical fiber relative to the needle. This results in practice, during the implementation of this device, a significant risk of sliding of the optical fiber relative to the needle, which increases the risk of rupture of the optical fiber inside the body of the device. patient.

A third disadvantage is related to the presence, between the optical fiber and the needle, of a gap allowing the penetration of tissue inside the needle. However, during the implementation of the laser, the tissues that penetrate between the needle and the optical fiber are burned by the laser. On the one hand, all or some of these burned tissues can detrimentally end up in inside the patient's body; on the other hand, they can damage the optical fiber.

The French patent application FR-A-2,875,122 describes a medical instrument applicable to vascular occlusion, and comprising, in an alternative embodiment, an optical fiber positioned inside a needle. This variant needle / optical fiber has the three disadvantages described above for the device of the publication US 6 206 873.

Document FR-A-2,875,122 proposes another solution in which the optical fiber is replaced by a silica electromagnetic radiation guide, integral with the needle; more particularly, this guide is formed by a "dressing" of the interior of the needle. The technical concept of "dressing" is not explained in this document and is not clear. However, the realization of such a guide inside a needle appears difficult to achieve; in addition, this type of device is not marketed to date, we can question its effectiveness.

US patent application US 2006/0078265 discloses a device consisting essentially of a laser energy source connected to a handpiece, and used to project a laser beam onto human tissues. The handpiece includes an optical fiber and a cannula enclosing the optical fiber. The distal portion of the optical fiber is this time entirely housed in the cannula. The cannula is closed at its distal end, and a lateral opening is provided in the cannula for lateral diffusion of the laser beam.

The protective sheath of the optical fiber was partially removed on a distal portion of the fiber, thus revealing the core of the optical fiber. The distal end of the sheath is abutted against three studs distributed over the periphery of the inner wall of the cannula, which allows a correct positioning of the distal end of the optical fiber relative to the lateral opening of the cannula allowing the diffusion of the laser beam. In the devices described in this publication US 2006/0078265, the problem of immobilization and maintenance of the optical fiber with respect to the cannula is not resolved. Thus, although the end of the optical fiber abuts against internal pads, the optical fiber can slide backwards; during the implementation of this device, the optical fiber is not properly immobilized and maintained in its distal portion, there is a risk of rupture of the core of the fiber at its distal end stripped.

In addition, there is, as in the other documents described above, a gap between the optical fiber and the cannula for the penetration of tissue.

Finally, in all the devices described in this publication US 2006/0078265, the laser emission is lateral and not frontal, and it is essential to place a reflector inside the needle to deflect the laser beam and spread it through the lateral opening of the cannula. The implementation of reflector complicates in a detrimental way the manufacture of the device. The publication US 2002/0138073 discloses a laser surgical probe using an optical fiber whose distal emission portion is housed inside a cylindrical tip. This cylindrical end is closed at its end by a mirror and the cylindrical wall of this endpiece is made of a material passing the laser beam delivered at the end of the fiber. This cylindrical tip allows lateral diffusion of the electromagnetic radiation delivered by the optical fiber and does not allow frontal emission. In addition, in order to obtain this lateral diffusion of the electromagnetic radiation, a diffusing medium is placed inside the cylindrical tip between the distal end of the optical fiber and the closed end of the tip.

The publication US 5,269,777 discloses a laser surgical probe using an optical fiber whose distal emission portion is inserted inside a silicone diffusion tip, which preferably has a length of 0.5 cm. and 5cm. This diffusion tip is attached to the distal end of the heart of the fiber, and does not constitute a cannula. After fixing this tip, a second inner layer diffusing is deposited inside the tip, for example by injection molding. This diffusing inner layer contains diffusing particles, such as, for example, diamond dust, TiO ₂ or alumina. The electromagnetic radiation, which is guided by the optical fiber to its distal end, is no longer guided at the output of the optical fiber inside the diffusion tip, but is diffused in all directions by the layer internal scattering of the tip.

OBJECT OF THE INVENTION According to a first aspect, the present invention is aimed primarily at proposing a new cannula / optical fiber assembly, which allows frontal emission of electromagnetic radiation, which makes it possible to reduce the risks of rupture of the optical fiber, and which allows a reliable immobilization of the optical fiber with respect to the cannula.

SUMMARY OF THE INVENTION According to this first aspect of the invention, the cannula / optical fiber assembly comprises a cannula, which comprises an opening at a distal end, and means for guiding an electromagnetic radiation. These guiding means comprise an optical fiber introduced inside the cannula, and used to guide electromagnetic radiation to the distal opening of the cannula, so that this electromagnetic radiation is emitted frontally by said distal opening of the cannula. the cannula. Said optical fiber comprises a core surrounded by an outer protective sheath, the outer diameter (Di) of the protective sheath of the optical fiber being substantially equal to the inner diameter (d ₂ ) of the cannula at least in a distal portion of said cannula . The core of the optical fiber is stripped on a distal portion of the fiber, and the stripped distal portion of the optical fiber is housed entirely within the cannula.

By the terms "substantially equal", it is meant that said outer diameter of the sheath of the optical fiber is very slightly less than the inside diameter of the cannula, with a functional clearance between the sheath of the optical fiber and the cannula which is just sufficient to allow the optical fiber to slide inside the cannula during the fiber introduction operation.

In the present text, the term "cannula" is taken in its most general acceptance and covers any elongated hollow support, curved or rectilinear, allowing the introduction and the guiding of the optical fiber in the human body. The cannula may in particular comprise a hollow tube whose distal end is rounded and non-aggressive to the tissues; the cannula may also comprise a hollow needle whose distal end is beveled and allows the piercing of tissues.

According to a second aspect of the invention that can be implemented independently of the first aforementioned aspect, the assembly of the invention comprises a cannula and means for guiding an electromagnetic radiation comprising an optical fiber which is introduced inside. Cannula the cannula is crimped on the optical fiber. According to this second aspect, the cannula can either be open at its distal end or be closed at its distal end and have in its distal part a lateral opening for the emission of electromagnetic radiation, in a manner comparable to the cannula / fiber assembly Optical described in US Publication 2006/0078265

According to a third aspect of the invention, which can be implemented independently of the above-mentioned first and second aspects, the assembly of the invention comprises a cannula which is open at its distal end, and means for guiding radiation. electromagnetic, which comprise an optical fiber introduced into the interior of the cannula, and which guide electromagnetic radiation to the open distal end of the cannula, said optical fiber having a core surrounded by an outer protective sheath. The core of the optical fiber is stripped at the distal end of the fiber; the distal portion of the optical fiber is housed entirely within the cannula, and the distal end of the optical fiber seals the distal opening of the cannula. Preferably, but optionally according to the invention, for the three aforementioned aspects, the cannula / optical fiber assembly has the following additional technical characteristics, taken separately or in combination: the cannula comprises in its distal part an insert hollow which has a through cavity, and the stripped distal portion of the core of the fiber is threaded into this hollow insert;

the sheath of the optical fiber is positioned in abutment inside the cannula; more particularly the sheath of the optical fiber is positioned in abutment against the insert;

- The stripped distal portion of the core of the fiber is housed entirely in the hollow insert;

the hollow insert is made of a thermally conductive material, and makes it possible to thermally protect the sheath of the optical fiber; the distal end of the heart of the optical fiber is flush with the distal opening of the cannula;

the stripped distal portion of the optical fiber closes the distal opening of the cannula, which advantageously makes it possible to prevent the penetration of foreign bodies into the cannula; the means for guiding the electromagnetic radiation comprise an additional guide fixed to the cannula, and the distal end of the heart of the optical fiber is preferably in contact with said additional guide; the additional electromagnetic radiation guide is flush with the distal opening of the cannula; the additional electromagnetic radiation guide closes the distal opening of the cannula, which advantageously makes it possible to prevent the penetration of foreign bodies into the cannula.

- The cannula is crimped on the sheath of the optical fiber, which allows a simple and effective immobilization of the optical fiber relative to the cannula. Another object of the invention is a laser instrument comprising a laser source coupled to the optical fiber of an assembly of the invention, said assembly being able to conform to the first, second or third aspect mentioned above. Brief description of the figures

The invention and its advantages will be better understood on reading the description which will follow, given solely by way of non-limiting and non-exhaustive example, and with reference to the appended figures in which: FIG. laser according to the invention,

- Figure 2 is a sectional representation of a cannula / optical fiber assembly in a first embodiment of the invention;

- Figure 3 is a sectional representation of a cannula / optical fiber assembly in a second embodiment of the invention;

- Figure 4 is a sectional representation of a cannula / optical fiber assembly in a third embodiment of the invention; - Figure 5 is a sectional representation of a cannula / optical fiber assembly in a fourth embodiment of the invention;

- Figure 6 is a sectional representation of a cannula / optical fiber assembly in a fifth embodiment of the invention;

- Figure 7 is a sectional representation of a cannula / optical fiber assembly in a sixth embodiment of the invention;

FIGS. 8 to 11 are sectional representations of a cannula / optical fiber assembly corresponding respectively to a seventh, eighth, ninth and tenth embodiment variant of FIG. the invention;

- Figures 12 and 13 show an optical fiber in a cannula at the end of a first step of a first method of assembly;

- Figures 14 and 15 show an optical fiber in a cannula at the end of a second step of said first method of assembly;

FIGS. 16 and 17 show an optical fiber in a cannula at the end of a third step of said first method of assembly; - Figures 18 and 19 show an optical fiber in a cannula at the end of a first step of a second method of assembly;

- Figures 20 and 21 show an optical fiber in a cannula at the end of a second step of said second method of assembly.

detailed description

With reference to FIG. 1, a laser instrument in accordance with the invention comprises a cannula / optical fiber assembly referenced E, on which is fitted a handpiece P, and a laser source S, which is coupled to the optical fiber of the invention. set E. The handpiece P is known per se and facilitates the handling and manipulation of the assembly cannula / optical fiber E. This laser instrument is intended to be used in the medical field, for any type laser treatment, and for example and non-limiting and non-exhaustive, for the treatment of varicose veins, for the treatment of adipose, for percutaneous diagnosis or in the field of ophthalmic surgery. It is up to the person skilled in the art to choose the laser source adapted to the uses of the laser instrument.

Different embodiments of the assembly cannula / optical fiber E will now be detailed.

In a first variant embodiment shown in FIG. the assembly E comprises an optical fiber 1 which makes it possible to guide by total internal reflections the electromagnetic radiation (light) delivered by the laser source S, and whose distal part (opposite to the laser source) is introduced to the 2. In FIG. 2, only the distal portion of the optical fiber 1 introduced into the cannula 2 and a distal portion of the cannula 2 are shown. In addition, the length of the cannula 2 may be more or less important depending on the applications.

The optical fiber 1 is known per se and comprises a core 10 for the guided propagation of the electromagnetic radiation delivered by the laser source, and a mechanical protection sheath 11, for example made of plastic, surrounding the core 10. As mentioned above, the The core of the optical fiber has a central portion for guided propagation of electromagnetic radiation and a thin intermediate layer, commonly referred to as "cladding", and surrounding the central portion for confining electromagnetic radiation in the central portion. In the appended figures, said central portion and said thin intermediate layer, which form the core of the optical fiber, are not differentiated.

The optical fiber has a diameter D ₁ (outer diameter of the sheath 11), and the core 10 of the fiber 1 has a diameter di. The distal portion 100 of the core 10 of the fiber 1 is stripped, that is to say that the protective sheath 11 does not cover the heart 10 and thus leaves said distal portion 100 of the heart 10. This avoids the risks burning of the sheath 11 by the laser beam emitted at the distal end 101 of the heart 10. The cannula 2 is constituted by a flexible tube opaque to electromagnetic radiation emitted by the laser source S, for example a flexible stainless steel tube. In the particular example illustrated, it comprises a cylindrical hollow body 20 extended by a substantially funnel-shaped hollow distal portion 21, said hollow body 20 and the hollow distal portion 21 defining a through internal cavity 22. In the following description, the outer face of the cannula 2 will be referenced 2a, and the inner face of the cannula 2 will be referenced 2b.

In the remainder of the description, the inside diameter of the cavity 22 in the portion of the cannula 2 corresponding to the cylindrical hollow body 20 is referenced d ₂ , and the outside diameter of the cannula 2 at the cylindrical hollow body 20 is referenced D ₂ .

The aforementioned distal portion 21 of the cannula 2 comprises a substantially frustoconical first portion 21a, which extends the cylindrical body 20 of the cannula 2, and whose cross section decreases towards the second cylindrical portion 21b of smaller diameter than the body The distal end 21c of the distal portion 21 of the cannula 2 is open (distal opening 210 aligned with the longitudinal axis of the cannula 2). In the particular example of FIG. 2, the diameter of the distal opening 210 of the cannula 2 is equal to the diameter of the cavity 22 of the cannula at the level of the second portion 21b mentioned above, and is referenced d ₃ in the following of the description. The outer diameter of the cannula 2 at the second portion 21b is referenced D ₃ .

Advantageously, the distal end 21c of the cannula 2 is rounded to limit the risks of tearing of the tissues of a patient during the introduction of the assembly E. The outer diameter Di of the sheath 11 of the fiber 1 is substantially equal to the inside diameter d ₂ of the cavity 22. By the terms "substantially equal", it is meant that the outside diameter Di of the sheath 11 of the optical fiber 1 is very slightly less than the inside diameter d ₂ of the cannula 2, with a functional clearance between the sheath 11 of the optical fiber 1 and the cannula 2 which is just sufficient to allow the sliding of the optical fiber 1 inside the cannula 2 during the operation of introducing the fiber. Typically, the difference in diameter (d ₂ -Di) is less than 100 μm and preferably less than 50 μm. As a result, on the one hand, the distal portion of the optical fiber 1 is reliably held inside the cannula 2. On the other hand, it is easy to reliably immobilize the optical fiber in translation 1 relative to the cannula 2, by localized clamping of the cannula 2 on the sheath 11 of the fiber 1, and for example, and as will be detailed later, by simply crimping the cannula 2 on the sheath 11 of the optical fiber 1.

Also, with reference to FIG. 2, the stripped distal portion 100 of the optical fiber 1 is housed entirely inside the cannula 2.

More particularly, the protective sheath 11 is abutted inside the cannula 2 against the inner face 2b of the first frustoconical portion 21a.

More particularly, as shown in FIG. 2, the distal end 101 of the bare core of the optical fiber is flush with the distal opening 210 of the cannula 2.

When introducing and manipulating the set E

(Cannula / fiber) in the human body, and advantageously avoids the risk of breakage of the stripped distal portion 100 of the core 10 of the optical fiber 1, which stripped distal portion 100 is more mechanically fragile.

More particularly still, in the example of FIG. 2, the diameter di of the core 10 of the fiber is substantially equal to the diameter ds of the distal opening 210 of the cannula 2. The denuded fiber core 10 thus closes the opening distal 210 of the cannula 2, and advantageously prevents the penetration of foreign bodies inside the cannula 2, and in particular the penetration of tissue during the displacement of the cannula 2 and the optical fiber 1 in the human body .

More particularly, but not necessarily, at the distal opening 210 of the cannula 2, the distal end of the fiber core may be glued within the distal end 21b of the cannula, for example by an activatable glue by ultraviolet radiation. This adhesive makes it possible to ensure, between the stripped core of the fiber and the inner wall of the cannula, a perfect seal preventing any penetration of foreign bodies into the interior of the cannula 2 through the distal opening 210. In operation, the totality of the electromagnetic radiation emitted by the laser source S is guided by total internal reflections by the optical fiber 1 to the open distal end 210 of the cannula 2, and all of this electromagnetic radiation is emitted frontal by this distal opening 210 of the cannula 2.

In a second embodiment of the invention shown in Figure 3, the distal portion 21 of the cannula 2 is substantially hemispherical. This substantially hemispherical rounded portion of the distal portion 21 makes it possible to pass from a diameter d ₂ of the cavity 22 to a smaller diameter. Thus, the protective sheath 11 is abutted inside the cannula 2 against the inner wall 2b of the hemispherical distal portion 21. In this variant, similarly to the first variant of FIG. 2, the stripped distal portion 100 of the core 10 of the optical fiber is housed entirely in the cannula 2, and the distal end 101 of the core 10 of the fiber 1 is flush with and closes the distal opening 210 of the cannula 2.

In a third embodiment of the invention shown in FIG. 4, the cannula 2 comprises a hollow cylindrical body

20 of outer diameter D ₂ and inner diameter d ₂ , and a cylindrical hollow insert 23. The insert 23 comprises a through internal cavity 230, and is fixed inside the hollow cylindrical body 20.

In this variant, this insert 23 is more particularly made of a thermally conductive material, and thus makes it possible to discharge, in the direction of the cannula 2, the heat produced by the laser beam, and to prevent propagation of said heat in the direction of the sheath 11 of the optical fiber 1. Of course, the insert 23 must be made of a heat-resistant material produced by the laser. In addition, this insert 23 acts as a mechanical stop for the protective sheath 11 of the optical fiber 1, and thus facilitates the positioning of the optical fiber in the cannula 2. For example, the insert 23 is made of metal, particularly in stainless steel, and is welded into the hollow cylindrical body 20, by laser, brazing or gluing. More particularly, the insert 23 has an outside diameter D ₃ and an inside diameter d ₃ , and is housed entirely inside the hollow cylindrical body 20, so that the distal end 231 of said insert 23 is flush with the distal opening 210 of the hollow body 20. The stripped distal portion 100 of the core 10 of the optical fiber 1 is housed entirely in the insert 23, the protective sheath 11 of the fiber 1 abuts inside the hollow body 20 against the insert 23. More particularly, the distal end 101 of the core 10 of the fiber 1 is flush with and closes the opening 232 of the distal end 231 of the insert 23. In this variant, the outer diameter D ₃ of the insert 23 is substantially equal to the diameter d ₂ of the cavity 22. Similarly, the inside diameter d3 of the insert is substantially equal to the diameter di of the core 10 of the fiber 1. Of course it is necessary to respect certain tolerances of play to allow the i ntroduction of the bare core of the fiber in the cavity 230 of the insert 23, and the introduction of the insert 23 into the cavity 22 delimited by the hollow body 20.

FIG. 5 shows a fourth variant of the invention that differs from the variant of FIG. 4 by implementing an insert 23 of different shape. This hollow insert 23 has a first cylindrical portion 23a, and a second portion 23b, having a larger cross section and hereinafter referred to as the head of the insert 23. The insert 23 is attached to the cylindrical hollow body 20 of the cannula 2 , so firstly that the tubular portion 23a of the insert 23 is housed entirely within the body 20, and secondly that the head 23b of the insert 23 abuts against the face of distal end 21c of the hollow body 20. In this embodiment, the stripped distal end 101 of the heart 10 of the optical fiber is projecting from the distal end face 21c of the hollow body 20, but is housed entirely in the insert 23 and is flush and closes the distal opening 232 of the head 23b of the insert 23. In a fifth embodiment of the invention shown in Figure 6, the cannula 2 is constituted by a hollow body cylindrical 20 of outer diameter D ₂ and inner diameter d ₂ . The optical fiber 1, of outer diameter Di, is positioned inside the cavity 22 of the cannula 2 so that the distal end 101 stripped of the core of the fiber 1 is flush with the distal opening 210 of the cannula 2, without however closing off this distal opening 210.

To manufacture the sets E (cannula / optical fiber) of Figures 2 to 6, two different manufacturing processes can be implemented.

A first manufacturing method is illustrated in Figures 12 to 17, and a second manufacturing method is illustrated in Figures 18 to 21. These two methods will now be detailed. It should be noted that in these figures, the cannula 2 and the optical fiber 1 illustrated correspond to the variant of Figure 3. Those skilled in the art can easily transpose these processes for the manufacture of other variants of Figs 2, 4, 5 and 6.

With reference to FIGS. 12 to 17, in order to manufacture the assembly E, in a first step (FIGS. 12 and 13), the cannula 2 is threaded onto the optical fiber 1, the core 10 of which has been previously stripped on a distal portion of the optical fiber, until the protective sheath 11 of the fiber is brought into abutment in the cannula. For the variant of FIG. 4 or of FIG. 5, the insert 23 has been previously fixed on the hollow body 20, and the stripped distal portion of the optical fiber is threaded into the insert 23, until the Protective sheath 11 of the fiber is brought into abutment against the insert 23. In a second step (FIGS. 14 and 15), crimping of the cannula 2 is preferably carried out so as to firmly immobilize the fiber 1 with respect to the cannula 2. The crimping allows the wall of the cannula 2 and the protective sheath 11 to be locally deformed so as to immobilize the sheath 11, and thus the fiber 1, in the cannula 2. When the crimping has been performed, radial deformations 4 are visible on the outer wall 2a of the cannula 2. These radial deformations 4 on the outer wall 2a of the cannula 2 cause deformations 4 'of the sheath 11 which block and prevent the sliding of the fiber 1 in the cannula 2. Finally, in a third step 2 (FIGS. 16 and 17) the core 10 of the optical fiber 1 is cut so that its distal end 101 is flush with the distal opening 210 of the cannula 2 [with the distal opening 232 of the insert 23 for the variant of Figure 5].

A second method, represented in FIGS. 18 to 21, consists in a first step (FIGS. 18 and 19) of stripping the optical fiber 1 for an appropriate length and inserting the optical fiber 1 into the cannula 2 so that the sheath 11 of the fiber abuts inside the cannula 2 and that the distal end 101 of the heart 10 of the fiber 1 is flush with the distal opening 210 of the cannula [or the distal opening 232 of the insert 23 for the variant of Figure 5]. Then, in a second step (FIGS. 20 and 21), the cannula 2 is crimped onto the sheath 11 to immobilize the fiber 1 in the cannula 2.

In the two methods that have just been described, the crimping of the cannula 2 on the fiber 1 is carried out in an area upstream of the zone of introduction of the set E into the human body, that is to say in an area that is not intended to be introduced into the human body.

In a sixth variant embodiment of the invention shown in FIG. 7, the cannula 2 is constituted by a tubular body 20 of external diameter D ₂ and of internal diameter d ₂ - an additional electromagnetic radiation guide 3, designated in the following light guide, is fixed inside and in the distal portion of the tubular body 20. This light guide 3 is made of any transparent material in the wavelength range of the laser source S, and in the example illustrated flush the distal opening 210 of the body 20 and closes the distal opening 210.

The stripped distal portion 100 of the core 10 of the optical fiber 1 is preferably positioned in abutment with this guide 3. The core 10 of the optical fiber, extended by the guide 3, forms with it a guide means for guiding by total internal reflection all the electromagnetic radiation emitted by the laser source S, up to the open distal end 210 of the body 20, and to emit frontally this electromagnetic radiation by the distal opening 210 of the cannula. In another alternative embodiment, the distal end 101 of the stripped distal portion 100 of the core 10 of the optical fiber 1 could be positioned near the light guide 3, without touching it; in this case, the distance between the distal end 101 of the core 10 of the optical fiber 1 and the light guide 3 must be sufficiently small, so that the electromagnetic radiation at the output of the core 10 of the fiber 1 is transmitted to the guide of light 3, without significant loss.

FIGS. 8 to 11 show alternative embodiments of the invention, which are different from the aforementioned variant of FIG. 7, by the implementation of light guides 3 'having a geometry different from the guide. 3 of Figure 7.

The aforementioned solution for immobilizing the optical fiber 1 with respect to the cannula 2, by crimping the cannula 2 with the sheath 11 of the optical fiber 1, can also be implemented in the variant embodiments of FIGS. 7 to 11. .

The invention is not limited to the variants of the appended figures, which have been described solely as exemplary embodiments. Other embodiments within the scope of those skilled in the art and covered by the appended claims may be envisaged, without departing from the scope of the invention.

Claims

An assembly (E) comprising a cannula (2) which comprises an opening (210) at a distal end (21c), and means for guiding an electromagnetic radiation, which comprise an optical fiber (1) introduced to the the interior of the cannula (2), and which guide electromagnetic radiation to the distal opening (210) of the cannula, such that this electromagnetic radiation is emitted frontally by said distal opening (210) of the cannula cannula (2), together in which said optical fiber (1) comprises a core (10) surrounded by an outer protective sheath (11), the outer diameter (Di) of the protective sheath (1 1) of the optical fiber ( 1) being substantially equal to the inner diameter (d2) of the cannula (2) at least in a distal portion of said cannula, the heart (10) of the optical fiber is stripped on a distal portion (100) of the fiber, and the stripped distal portion (100) of the optical fiber is housed entirely at the i inside the cannula (2).

2. An assembly according to claim 1, characterized in that the cannula (2) has in its distal portion (21) a hollow insert (23) which has a through cavity (230), and in that the distal distal portion (100) ) of the core (10) of the fiber is threaded into this hollow insert (23).

3. An assembly according to claim 1 or 2, characterized in that the sheath (11) of the optical fiber (1) is positioned in abutment within the cannula (2).

4. An assembly according to claims 2 and 3, characterized in that the sheath (11) of the optical fiber (1) is positioned in abutment against the insert (23).

5. An assembly according to one of claims 2 to 4, characterized in that the stripped distal portion (100) of the core (10) of the fiber is housed entirely in the hollow insert (23).

6. Assembly according to one of claims 2 to 5, characterized in that Hollow pinsert (23) is made of a thermally conductive material, and thermally protects the sheath (11) of the optical fiber.

7. Assembly according to one of claims 1 to 6, characterized in that the distal end (101) of the heart (10) of the optical fiber (1) is flush with the distal opening (210 or 232) of the cannula ( 2).

8. Assembly according to one of claims 1 to 7, characterized in that the stripped distal portion (100) of the optical fiber closes the distal opening (210 or 232) of the cannula (2).

9. The assembly of claim 1, characterized in that the means for guiding an electromagnetic radiation comprise an additional guide (3) attached to the cannula (2).

10. The assembly of claim 9, characterized in that the additional guide (3) is flush with the distal opening (210) of the cannula (2).

11. The assembly of claim 9 or 10, characterized in that the additional guide (3) closes the distal opening (210) of the cannula

(2).

12. The assembly according to Pune-claims 1 to 11, characterized in that the cannula (2) is crimped on the sheath (11) of the optical fiber (1).

13. Laser instrument, characterized in that it comprises a set (E) according to one of claims 1 to 12, and a laser source (S) coupled to the optical fiber (1) of this set (E).